Vessel for transferring thermal energy to and inducing convection in a contained fluid

ABSTRACT

An article of manufacture includes a wall portion having a wall inner surface and a wall outer surface, a base portion having a base inner surface and a base outer surface, at least a portion of the wall portion and the base portion forming a vessel to retain fluid therein, at least part of the base portion configured to receive heat, and a plurality of shaped portions extending above, each shaped portion of the base inner surface including at least three sides, the top of each being hexagonal in shape, each of the plurality of shaped portions capable of supplying heat from the sides to fluid adjacent to the sides, the plurality of shaped portions including the hexagonal shaped tops to assist in uneven heat transfer from the heating source to the fluid retained in the article of manufacture.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Nonprovisional applicationSer. No. 14/599,131, entitled “Vessel for Transferring Thermal Energy toand Inducing Convection in a Contained Fluid,” filed Jan. 16, 2015,which is a continuation-in-part of and seeks priority to U.S.Nonprovisional application Ser. No. 14/331,119, entitled “Vessel forTransferring Thermal Energy to a Contained Fluid,” filed Jul. 14, 2014,which are incorporated by reference herein.

BACKGROUND

Vessels are used to contain substances such as fluids. A vessel is anyhollow container including, for example, a container manufactured tohold a fluid (e.g., water, liquid, substance, or liquid/solid mixtures)and to facilitate the transfer of thermal energy to the substance (e.g.,fluid) contained within. Examples of such vessels include pots, kettles,and the like.

Such vessels in the prior art such as pans or skillets typically includea flat bottom or a bottom that is indented around a perimeter of thebottom. Even with such an indentation, the bottom of such vessels isprimarily flat. The bottom of the vessel is generally set against a heatsource (e.g., flame or heating element). The heat source transfersthermal energy through the flat bottom of the vessel and into the fluidtherein. There may be design elements or reinforcement elements on thevessel or the bottom of the vessel.

Marketing materials for vessels in the prior art tout the benefits ofuniform heating. Uniform heating has merit if heating is purely byconduction (i.e., thermal diffusion), or, if the contents being heatedare “fragile”, in the sense that they are subject to thermaldegradation.

Essentially, the same vessel has been used worldwide. Differences invessels of the same type are generally cosmetic, based on durability,based on ergonomics, or fabricated from different material(s).

SUMMARY

An example article of manufacture includes a wall portion having a wallinner surface and a wall outer surface, a base portion having a baseinner surface and a base outer surface, at least a portion of the wallportion and the base portion forming a vessel to retain fluid therein,at least part of the base portion configured to receive heat from aheating source, and a plurality of shaped portions extending above thebase inner surface or the wall inner surface, a top of each of theplurality of shaped portions being opposite a bottom of each of theplurality of shaped portions, each shaped portion of the base innersurface including at least three sides extending from the bottom to thetop, the top of each of the plurality of shaped portions being hexagonalin shape, each of the plurality of shaped portions capable of supplyingheat from the sides to fluid adjacent to the sides of at least one othershaped portion of the plurality of shaped portions, the plurality ofshaped portions of the base inner surface or the wall inner surfaceincluding the hexagonal shaped tops of the plurality of shaped portionsand sides of the plurality of shaped portions to assist in uneven heattransfer from the heating source to the retained fluid in the article ofmanufacture.

In various embodiments, wherein the article of manufacture is a kettle,at least two of the plurality of shaped portions may have differentheights extending above the base inner surface or the wall innersurface. The base portion may comprise at least two different metals.Each of the plurality of shaped portions may be hexagonal in shape.

In some embodiments, subsets of the plurality of shaped portions areevenly arranged. The subsets of the plurality of shaped portions may bearranged in one or more lines. The plurality of shaped portions of thebase inner surface or the wall inner surface including the hexagonalshaped tops of the plurality of shaped portions and the sides of theshaped portions may be configured to assist in uneven heat transfer intothe fluid retained in the article of manufacture and to decrease thetime needed to heat the fluid to a desired temperature.

The article of manufacture may be a pot. The base outer surface furthermay comprise one or more other shaped portions extending from the baseouter surface, the one or more other shaped portions to assist in unevenheat transfer from the heating source to the fluid in the article ofmanufacture. The plurality of shaped portions of the base inner surfaceor the wall inner surface including the hexagonal shaped tops of theplurality of shaped portions and the sides of the shaped portions may beconfigured to assist in creation of at least one two-armed spiral in thefluid that rotates. The plurality of shaped portions of the base innersurface or the wall inner surface including the hexagonal shaped tops ofthe plurality of shaped portions and the sides of the shaped portionsmay be configured to induce one or more dislocations in any of the atleast one two-armed spiral. The plurality of shaped portions of the baseinner surface or the wall inner surface including the hexagonal shapedtops of the plurality of shaped portions and the sides of the shapedportions may be configured to assist in creation of a plurality ofthree-dimensional cells (e.g., convection cells) in the fluid in thearticle of manufacture.

In various embodiments, the plurality of shaped portions of the baseinner surface or the wall inner surface including the hexagonal shapedtops of the plurality of shaped portions and the sides of the shapedportions may be configured to assist in creation of a plurality ofthree-dimensional cells in contact with the surface of the fluid in thearticle of manufacture. The plurality of shaped portions of the baseinner surface or the wall inner surface may be arranged in at least onecircular pattern. The plurality of shaped portions of the base innersurface or the wall inner surface may be arranged in at least one lineradiating out from a center of the base inner surface.

In some embodiments, the hexagonal shaped tops may be configured toprovide nucleation points to assist and promote bubble nucleation forthe onset of rapid boiling. Further, in some embodiments, the nucleationpoints may assist with an onset of rapid boiling and avoids superheatingthe fluid to avoid dangerous pressures and spills.

The hexagonal shaped tops may be configured to assist in the formationof G-cell convection cells in contact with the surface of the fluid inthe article of manufacture. In some embodiments, the heating source iswithin the base portion.

An example method comprises receiving one or more metals, forming themetals into a kettle, the kettle including a wall portion, a baseportion, and a plurality of shaped portions, the wall portion having awall inner surface and a wall outer surface, the base portion having abase inner surface and a base outer surface, at least a portion of thewall portion and the base portion forming a vessel to retain fluidtherein, at least part of the base portion configured to receive heatfrom a heating source, and the plurality of shaped portions extendingabove the base inner surface or the wall inner surface, a top of each ofthe plurality of shaped portions being opposite a bottom of each of theplurality of shaped portions, each shaped portion of the base innersurface including at least three sides extending from the bottom to thetop, the top of each of the plurality of shaped portions being hexagonalin shape, each of the plurality of shaped portions capable of supplyingheat from the sides to fluid adjacent to the sides of at least one othershaped portion of the plurality of shaped portions, the plurality ofshaped portions of the base inner surface or the wall inner surfaceincluding the hexagonal shaped tops of the plurality of shaped portionsand sides of the plurality of shaped portions to assist in uneven heattransfer from the heating source to the retained fluid in the article ofmanufacture.

An article of manufacture is configured to transfer thermal energy to acontained substance. This article of manufacture may be a vessel such asa kettle, pot, or pan. The substance may include a fluid, a liquid, or amixture of a liquid and a solid. In some embodiments, the article ofmanufacture includes a wall portion having a wall inner surface and awall outer surface; a base portion having a base inner surface and abase outer surface, at least a portion of the wall portion and the baseportion forming a vessel to retain fluid therein, at least part of thebase portion configured to receive heat from a heating source, and atleast one of: a shaped portion of the base outer surface being shaped tohave substantially more surface area in thermal contact with the heatingsource than a flat base outer surface so as to receive additional heatfrom the heating source, or a shaped portion of the base inner surfaceshaped to have substantially more surface area in thermal contact withthe fluid than a flat base inner surface to transfer additional heatfrom the heat source to the retained fluid.

In some embodiments, a shaped surface is corrugated to include aplurality of ridges and furrows. In some embodiments the ridges andfurrows are shaped as a sinusoidal wave. In some embodiments, the ridgesand furrows are shaped as a square wave. The ridges and furrows causethe surface area of the shaped surface to be substantially increased.

In some embodiments, a shaped surface includes a plurality ofprotrusions and/or indentations. In some embodiments the protrusions areshaped and positioned as sinusoidal waves. In some embodiments theplurality of protrusions are shaped and positioned as square waves. Theprotrusions may cause the surface area of the shaped surface to besubstantially increased.

In various embodiments, the shaped portion of the base outer surface isshaped to have 1.2 or more times the surface area than the flat baseouter surface. The shaped portion of the base inner surface may beshaped to have 1.2 or more times the surface area than the flat baseinner surface.

These and other advantages will become apparent to those skilled in therelevant art upon a reading of the following descriptions and a study ofthe several examples shown in the drawings. The drawings are includedfor illustrative purposes and are not intended to limit possible orpotential shapes, patterns, or locations of protrusions and/orindentations.

An article of manufacture includes a wall portion having a wall innersurface and a wall outer surface. The article of manufacture alsoincludes a base portion having a base inner surface and a base outersurface. At least a portion of the wall portion and the base portionform a vessel to retain a fluid therein. The article of manufacture alsohas a shaped portion of the base inner surface or the wall innersurface. A first section of the shaped portion may have a first surfacearea in thermal contact with the fluid. A second section of the shapedportion may have a second surface area in thermal contact with thefluid. The first and second surface areas may be different therebyinducing convection within the fluid that increases heat transfer fromthe heat source to the fluid.

In various embodiments, the shaped portion may be corrugated, and mayinclude a plurality of ridges and furrows. Different ridges of theplurality of ridges may have different heights. In some embodiments,different furrows of the plurality of furrows may have different depths.The plurality of ridges and furrows may be shaped as a wave, such thatridge sides of the plurality of ridges are curved towards ridge topplanes of the ridges, and furrow sides of the plurality of furrows arecurved towards furrow bottom planes of the furrows. A ridge of theplurality of ridges may be shaped such that a ridge cross section of theridge exhibits reflection symmetry about a ridge axis of symmetry normalto a ridge top plane of the ridge. A furrow of the plurality of furrowsmay be shaped such that a furrow cross section of the furrow exhibitsreflection symmetry about a furrow axis of symmetry normal to the furrowbottom plane of the furrows.

At least some of the shaped portion may include a first material andsome of the shaped portion may include a second material. The first andsecond materials may have different thermal diffusivities.

The plurality of ridges and furrows may be shaped as a square wave, suchthat ridge sides of the plurality of ridges extend up to a ridge topplane of a ridge that extends across a top of the ridge, and furrowsides of the plurality of furrows extend down to a furrow bottom planeof a furrow that extends across a bottom of the furrows.

The plurality of ridges and furrows of the shaped portion may beconcentrically positioned about a corresponding center of the base innersurface.

In some embodiments, the plurality of ridges and furrows of the shapedportion radiate out from a corresponding center of the base innersurface. The plurality of ridges and furrows of the shaped portion maybe parallel to each other. In various embodiments, at least one of theplurality of ridges or furrows radiates out from a center of the baseportion at an increasing width.

The shaped portion may include a plurality of protrusions to cause thecorresponding base outer surface or the base inner surface to havesubstantially more surface area than a corresponding flat base outersurface or flat base inner surface. The plurality of protrusions may bepositioned in an array that includes a plurality of protrusion rows andprotrusion columns. The protrusions of the plurality of protrusionswithin at least one of a protrusion row of the plurality of protrusionrows or a protrusion column of the plurality of protrusion columns maybe shaped as a wave, such that protrusion sides of the protrusionswithin at least one of the protrusion row or the protrusion column curveupward towards a protrusion plane at a protrusion height. Theprotrusions of the plurality of protrusions may exhibit reflectionsymmetry about a protrusion axis of symmetry normal to the protrusionplane.

In some embodiments, the protrusions of the plurality of protrusionswithin at least one of a protrusion row of the plurality of protrusionrows or a protrusion column of the plurality of protrusion columns areshaped as a square wave, such that protrusion sides of the protrusionswithin at least one of the protrusion row or the protrusion columnextend upward towards a protrusion top plane, the protrusion top planeextending across protrusion tops of the protrusions within at least oneof the protrusion row or the protrusion column. The plurality ofprotrusions may be positioned in protrusion rings that areconcentrically positioned about a corresponding center of the base innersurface. The plurality of protrusions may be positioned in thecorresponding base outer surface or the base inner surface in protrusionradials that radiate out from a corresponding center of the base innersurface.

The shaped portion may include a plurality of indentations to cause thecorresponding base outer surface or the base inner surface to havesubstantially more surface area than a corresponding flat base outersurface or flat base inner surface. The indentations of the plurality ofprotrusions may have different indentation heights. The plurality ofindentations may be positioned in an array that includes a plurality ofindentations rows and indentations columns. In various embodiments, anarticle of manufacture comprises a wall portion having a wall innersurface and a wall outer surface, a base portion having a base innersurface and a base outer surface, at least a portion of the wall portionand the base portion forming a vessel to retain fluid therein, at leasta heating surface portion of the base outer surface positioned toreceive heat from a heating source, and a shaped portion of the baseinner surface or the wall inner surface, with a first section of theshaped portion having a first thickness and a second section of theshaped portion having a second thickness, the first and second sectionsbeing in thermal contact with the fluid, the first and secondthicknesses being different which induces convection within the fluidthat increases heat transfer from the heat source to the fluid.

In some embodiments, an article of manufacture comprises a wall portionhaving a wall inner surface and a wall outer surface, a base portionhaving a base inner surface and a base outer surface, at least a portionof the wall portion and the base portion forming a vessel to retainfluid therein, at least a heating surface portion of the base outersurface positioned to receive heat from a heating source, and a shapedportion of the base inner surface or the wall inner surface, with afirst section of the shaped portion having a first material and a secondsection of the shaped portion having a second material, the first andsecond sections being in thermal contact with the fluid, the first andsecond materials having different thermal diffusivities which inducesconvection within the fluid that increases heat transfer from the heatsource to the fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a perspective view of an example of a kettle fortransferring thermal energy to a contained fluid such as water, aliquid, a substance, or a mixture of a liquid and a solid (e.g., soup).

FIG. 2A is a planar view of an example kettle bottom surface with acavity defined between an edge of the base of the kettle and a thickmetal encapsulated base in the prior art.

FIG. 2B is a cross section view of an example kettle bottom surface witha cavity defined between an edge of the base of the kettle and a thickmetal encapsulated base in the prior art.

FIG. 2C includes dimensions for the cross section view of FIG. 2B.

FIG. 3 is a cross sectional view of a vessel (e.g., a portion of thekettle) in some embodiments.

FIG. 4 is a planar view of an example shaped surface that is corrugatedaccording to an example pattern.

FIG. 5 is a planar view of an example shaped surface that is corrugatedaccording to another example pattern.

FIG. 6 is a planar view of an example shaped surface that is corrugatedaccording to another example pattern.

FIG. 7A is a cross-sectional view of a shaped surface that includesridges and furrows shaped according to a sinusoidal wave.

FIG. 7B is a cross-sectional view of a shaped surface that is corrugatedwith ridges and furrows shaped according to a square wave.

FIG. 8 is a planar view of a shaped surface that is corrugated accordingto another example pattern.

FIG. 9 is a planar view of a shaped surface that is corrugated accordingto another example pattern.

FIG. 10 is a planar view of a shaped surface with a plurality ofprotrusions according to a protrusion pattern.

FIG. 11 is a planar view of a shaped surface with a plurality orprotrusions according to another protrusion pattern.

FIG. 12 is a planar view of a shaped surface with a plurality orprotrusions according to another protrusion pattern.

FIG. 13 is a planar view of a shaped surface with a plurality orprotrusions according to another protrusion pattern.

FIG. 14A is a cross-sectional view of a shaped surface with protrusionsshaped as a sinusoidal wave.

FIG. 14B is a cross-sectional view of a shaped surface with protrusionsshaped as a square wave.

FIG. 15A depicts interlocking elbow shaped surfaces in some embodiments.

FIG. 15B depicts conical shaped protrusions in some embodiments.

FIG. 15C depicts conical shaped indentations in some embodiments.

FIG. 15D depicts triangular shaped protrusions in some embodiments.

FIG. 15E depicts triangular shaped indentations in some embodiments.

FIG. 15F depicts dimple shaped indentations in some embodiments.

FIG. 15G depicts dimple shaped protrusions in some embodiments.

FIG. 16A is a cross-sectional view of a shaped surface with roundedprotrusions.

FIG. 16B is a cross-sectional view of a shaped surface with protrusionsshaped as a square wave.

FIG. 17 is a planar view of a shaped surface with a plurality orprotrusions according to another protrusion pattern.

FIG. 18A is a planform schematic diagram of two-dimensional rolls ofconvection cells.

FIG. 18B is a planform schematic diagram of hexagonal L- and G-cells.

FIG. 19 is a two-armed spiral in a fluid that rotates clockwise in someembodiments.

FIG. 20A depicts texture in a rectangular container (the neighborhoodsof the short container walls are not visible).

FIG. 20B depicts a schematic image of a texture in a circular container(dashed lines indicate the main features of the structure of the largescale flow).

FIG. 21A depicts concentric rolls formed with stronger forcing.

FIG. 21B depicts concentric rolls formed with weaker forcing andsuperposed by short crossed rolls near the wall.

FIG. 21C depicts straight rolls formed from a disordered pattern.

FIG. 22 depicts eccentric annular rolls in a cylindrical vessel in someembodiments.

DETAILED DESCRIPTION

FIG. 1 depicts a perspective view of an example of a kettle 100 fortransferring thermal energy to a contained fluid such as water, aliquid, a substance, or a mixture of liquid and a solid (e.g., soup).While the kettle 100 is provided as one example, in other embodimentsany container (e.g., a vessel) may be utilized such as, but not limitedto, a pot, pan, or any other container which may hold a substance. Insome embodiments, various embodiments described herein may be utilizedwith a cooking implement.

The kettle 100 includes a base portion 102 and a wall portion 104. Thebase portion 102 and the wall portion 104 may be formed from a singlepiece of material or, alternately, by multiple pieces of material. Thekettle may be formed in any number of ways such as, for example, weldingor crimping the base portion 102 to the wall portion 104. The baseportion 102 and the wall portion 104 may be comprised of one or aplurality of applicable materials that may assist in containing thesubstance and/or transferring thermal energy from the outside of thekettle 100 to the inside of the kettle 100.

The kettle 100 may comprise any kind of material. For example, the baseportion 102 and/or the wall portion 104 may comprise material such as,but not limited to, stainless steel, copper, ceramic(s), and/or thelike. The base portion 102 and/or the wall portion 104 may comprise analloy or any combination of materials. In some embodiments, the baseportion 102 and the wall portion 104 may include a sandwich structure ofvarious layers of materials. For example, the base portion 102 and/orthe wall portion 104 may be clad and include a layer of copper,aluminum, or other metal(s) sandwiched between layers of steel (e.g.,between layers of stainless steel).

The base portion 102 and the wall portion 104 may combine to create avessel 106 that functions to contain a volume of a substance. In variousembodiments, the kettle 100 may be referred to as a vessel or, in someembodiments, the kettle may comprise a vessel. The vessel 106 is aportion of the kettle 100 that may contain or hold the substance. Invarious embodiments, the kettle 100 receives heat from an external heatsource and transfers heat through the base 102 to the containedsubstance.

In various embodiments, the base portion 102, and potentially, the wallportion 104 are in thermal contact with the substance (e.g., fluid)contained within the kettle 100. In some embodiments, the thermalcontact enables thermal energy to transfer from or through the baseportion 102 and/or the wall portion 104 to the contained substance(e.g., held by the vessel 106). For example, the substance is in thermalcontact with the base portion 102 because the substance within thekettle 100 is in physical contact with the base portion 102 and/or wallportion 104. In transferring thermal energy to the contained substance,the base portion 102 and/or the wall portion 104 may, in someembodiments, absorb thermal energy from a thermal energy source (e.g.,fire, heating element, or the like such as, but not limited to,electric, ceramic, halogen, gas, hydrocarbon(s), or induction heatingelements). Further in transferring thermal energy to a containedsubstance, the base portion 102 and/or the wall portion 104 can transferenergy absorbed from the thermal energy source to the containedsubstance. It will be appreciated that the thermal energy source may beexternal to the kettle 100 (e.g., a stove or fire). In another example,the thermal energy source may be internal to the kettle 100 (e.g., anelectric kettle or any other electrically heated vessel).

In an example of operation, the base portion 102 and/or the wall portion104 may absorb thermal energy from many different types of thermalenergy sources. In various embodiments, the base portion 102 and/or wallportion 104 may receive thermal energy from, but not limited to,conduction, convection, induction, or radiation heating. Additionally,the base portion 102 and/or the wall portion 104 can transfer absorbedthermal energy to the contained substance and/or facilitate convectionin the contained substance.

The kettle 100 includes a receiving aperture 108. The receiving aperture108 is an opening through which the substance (e.g., fluid such as aliquid, or mixture of a liquid and a solid) may be passed out of and/orinto the vessel 106. In some embodiments, once the substance iscontained within the vessel 106, thermal energy can be transferred fromthe external heating source through the base portion 102 and/or the wallportion 104.

The kettle 100 includes a dispensing aperture 110. The dispensingaperture 110 is an opening through which the substance may be passed outfrom the vessel 106. The dispensing aperture 110 may be shaped to allowfor the pouring of the substance. In some embodiments, the dispensingaperture 110 passes heated fluid after a desired amount of thermalenergy is transferred to the fluid. For example, the dispensing aperture110 may be used to pass a contained liquid out of the vessel 106 afterenough thermal energy is transferred to the liquid contained within thevessel 106 to cause the liquid to boil, or to cause the liquid to reacha desired temperature.

FIG. 2A is a planar view of an example kettle bottom surface with acavity defined between an edge 208 of the base of the kettle and a thickmetal encapsulated base 202 in the prior art. In the prior art, somekettles include a thick aluminum encapsulated base (or otherencapsulated metal) for uniform or even heating. In this example, thethick metal encapsulated base 202 is flat and is a major portion (e.g.,a predominant portion) of the bottom of the kettle. An encapsulated baseedge 204 and edge 208 of the kettle may define a cavity 206 along therim of the base of the kettle. A diameter 210 is a diameter of the baseof the kettle.

The edge 208 may allow for the thick metal encapsulated base 202 to becoupled to the bottom of the kettle. The edge 208 and cavity 206 mayalso help capture the edge of stove flames to entrap heat. Althoughthere is an increase in surface area, the increase in heat transfer isnominal because the increase in the surface area is nominal.

FIG. 2B is a cross section view of an example kettle bottom surface witha cavity 206 defined between an edge 208 of the kettle and a thick metalencapsulated base 202 in the prior art. In this cross-sectional view,the cavity 206 is shown between the edge 208 of the kettle and theencapsulated base 202. As can be seen, there is not a substantial orsignificant increase in surface area of the bottom when compared to akettle with a flat bottom.

FIG. 2C includes dimensions for the cross section view of FIG. 2B. Here,dimension “d1” represents the diameter of the thick metal encapsulatedbase 202. Dimension “d2” represents the diameter of the base of thekettle (e.g., diameter 210). Dimension “h” represents the distance thatthe thick metal encapsulated base 202 extends perpendicularly from thebase of the periphery of the kettle. Given these dimensions, theincrease in surface area for the kettle bottom surface in FIG. 2Crelative to a kettle with a flat bottom surface is:

-   Δarea=(area of this example kettle bottom surface)−(area if the    kettle bottom surface was flat)

With the dimensions shown in FIG. 2C:

${\Delta\;{area}} = {(\pi)(h)\left( {{d\; 2} + {\left( {\left( \frac{\sqrt{2}}{2} \right) - 1} \right)\left( {d\; 1} \right)} + {\left( {\sqrt{2} - 1} \right)(h)}} \right)}$

The percentage increase in the surface area for this example kettlebottom surface relative to the surface area if the kettle bottom surfacewas flat equals:

(100%)(Δarea)/(area if the kettle bottom surface was flat)

For example, using the dimensions as labeled in FIG. 2C, a kettle withapproximate dimensions of d1=7 inch, d2=9 inch, and h=¼inch, will have apercentage increase in the surface area of approximately ten percent(e.g., 10%) relative to a kettle with a flat bottom. This percentageincrease in the surface area (of this kettle in the prior art) isnominal, and it does not significantly or appreciably increase thesurface area (relative to a flat bottom surface) such that the thermaltransfer would also significantly or appreciably increase.

FIG. 3 is a cross sectional view of a vessel 106 (e.g., a portion of thekettle 100) in some embodiments. The vessel 106 is formed by a baseportion 102 and a wall portion 104. The base portion 102 includes a baseouter surface 302 and a base inner surface 304. The base outer surface302 is the surface opposite of the base inner surface 304.

In various embodiments, the base outer surface 302 is the surface of thebase portion 102 through which thermal energy is received from thethermal energy source. The base outer surface 302 may include a heatingsurface portion that receives and absorbs heat from the thermal energysource. The base inner surface 304 is the surface of the base portion102 through which absorbed thermal energy may be transferred to thecontained substance (e.g., a fluid contained or held within the vessel106). Thus, the base portion 102 may be thermally coupled to thesubstance contained within the vessel 106 through the base inner surface304. In various embodiments, the base inner surface 304 may physicallycontact at least some of the substance contained within the vessel 106,and thereby be thermally coupled to the substance contained within thevessel 106.

In some embodiments, at least one of the base outer surface 302 and/orthe base inner surface 304 includes a shaped portion. A shaped portionof the base outer surface 302 or the base inner surface 304 is shapedsuch that there is substantially more surface area when compared to aflat surface. A shaped portion of the base outer surface 302 mayinclude, for example, raised rectangular ridges, raised sinusoidalridges, raised rectangular ridges, posts, raised portions, protrusions,indentations, or the like of any size or shape. A shaped portion mayinclude raised portions of a surface, depressed portions in the surface,or a combination of raised portions and depressed portions (e.g., acombination of protrusions and indentations) of the surface.Substantially more surface area may, for example, include 1.2 or moretimes (e.g., 1.5 times or more, 2 times or more, 3 times or more, or thelike) of a surface area when compared to the surface area of a flatsurface. Examples of shaped portions with substantially increasedsurface area (in comparison with a flat surface), are described herein.In various embodiments, only a portion of the base outer surface 302and/or the base inner surface 304 includes shaped portions.

The wall portion 104 includes a wall outer surface 306 and a wall innersurface 308. The wall outer surface 306 is opposite the wall innersurface 308. In some embodiments, all or a portion of the wall outersurface 306 may receive thermal energy from the thermal energy source. Aportion of the wall inner surface 308 may transfer thermal energy fromthe wall outer surface 306 to the contained fluid. Thus, a portion ofthe wall portion 104 may be thermally coupled to the contained fluid. Invarious embodiments, the wall inner surface 308 may physically contactat least some of the fluid contained within the vessel 106, and therebybe thermally coupled to the substance contained within the vessel 106.

In some embodiments, at least a portion of the wall outer surface 306and/or at least a portion of the wall inner surface 308 include a shapedportion. A shaped portion of the wall outer surface 306 or the wallinner surface 308 is shaped such that the shaped portion hassubstantially more surface area than if the shaped portion of thecorresponding wall outer surface 306 or wall inner surface 308 was flat.

A shaped portion of the wall outer surface 306 and/or the shaped portionof the wall inner surface 308 may include, for example, raisedsinusoidal ridges, raised rectangular ridges, indented sinusoidalfurrows, indented rectangular ridges, posts raised portions, depressedportions, protrusions, indentations, or the like of any size or shape. Ashaped portion may include raised portions of a surface, depressions inthe surface, or a combination of raised portions and depressed portions(e.g., a combination of protrusions and indentations) of the surface.Examples of shaped portions with substantially increased surface area(in comparison with a flat surface), are described herein. In variousembodiments, only a portion or the entire wall outer surface 306 and/oronly a portion of the wall inner surface 308 includes a shaped portion.

A base inner surface 304 and/or a wall inner surface 308 withsubstantially more surface area than a flat corresponding portion willincrease the rate at which thermal energy is transferred to a substancecontained within the vessel 106 (e.g., substantially increased). Forexample, the rate that thermal energy is transferred to the volume ofsubstance may be directly proportional to the surface area of the volumeof fluid in thermal contact with the heated surface(s) (e.g., wall innersurface 308 and/or base inner surface 304). Increasing the surface areaof the base inner surface 304 of the base portion 102, and/or the wallinner surface 308 (e.g., with protrusions, ridges, fins, furrows,indentations, and/or the like) increases the surface area of contactbetween a contained substance in the vessel 106 and at least a portionof the base inner surface 304 and/or at least a portion of the wallinner surface 308. Due to the (e.g., substantially) increased surfacearea between the substance and the base inner surface 304 and/or thewall inner surface 308, the rate of heat transfer from the thermalenergy source (e.g., from a heat source via the base outer surface 302)to the substance contained in the vessel 106 may be (e.g.,substantially) increased.

Similarly, increasing the surface area of the base outer surface 302 ofthe base portion 102, and/or the wall outer surface 306 (e.g., withprotrusions, ridges, fins, indentations, and/or the like of any size orshape) may increase the surface area of contact between the thermalenergy provided by the heat source and at least a portion of the baseouter surface 302 of the base portion 102, and/or the wall outer surface306. Due to the (e.g., substantially) increased surface area between thethermal energy of the heat source and the base outer surface 302 and/orthe wall outer surface 306, the rate of heat transfer from the thermalenergy source (e.g., from a heat source via the base outer surface 302and/or the wall outer surface 306) to the substance contained in thevessel 106 may be (e.g., substantially) increased.

Increasing the amount of thermal energy that is absorbed by, orincreasing the amount of thermal energy which transfers through, orincreasing the flux of thermal energy which transfers through, orincreasing the rate at which thermal energy transfers through at least aportion of the base portion 102 and/or at least a portion of the wallportion 104 may increase the temperature difference between the baseportion 102 and/or the wall portion 104 and a substance contained withinthe vessel 106. Increasing the temperature difference between at least aportion of the base portion 102 and/or at least a portion of the wallportion 104 relative to a substance contained within the vessel 106 maylead to an increased rate at which thermal energy is transferred fromthe base portion 102 and/or the wall portion 104 to the substance. As aresult of increasing the rate at which thermal energy is transferredfrom the base portion 102 and/or the wall portion 104 to the substancecontained within the vessel 106, more thermal energy is transferred tothe substance during a specific (e.g., limited) amount of time. In oneexample, a fluid may heat up, or boil, faster as a result of the (e.g.,substantially) increased surface area(s) of the base portion 102 andwall portion 104.

In some embodiments, in configuring a portion of a base inner surface304 and/or a wall inner surface 308 to be shaped to have more surfacearea than a corresponding portion of the surface that is flat, a greateramount of thermal energy is transferred from a heat source to asubstance contained within the vessel 106. Increasing the surface areaof the base inner surface 304 and/or the wall inner surface 308 mayincrease the amount of surface area that is in thermal contact with asubstance contained within the vessel 106. As a result of increasing theamount of surface area that is in thermal contact with a substancecontained within the vessel 106 and/or in thermal contact with a heatsource, an increased amount of thermal energy may be absorbed by, orotherwise transferred to, the substance during a specific (e.g.,limited) amount of time.

It will be appreciated that the thermal energy source may be external(i.e., separate) the vessel 106. For example, the thermal energy sourcemay be a fire or heating element on a stove. In this example, thethermal energy source (or a component of the thermal energy source) maynot be integral to, fixed to, or permanently attached to the vessel 106.In some embodiments, the thermal energy source may be configured orarrayed within a horizontal zone below the vessel 106.

In some embodiments, the thermal energy source may be internal to thevessel 106 (e.g., contained within the base of the vessel 106). Forexample the thermal energy source may be between the base outer surface306 and the base inner surface 304. In this example, the thermal energysource may be internal to the vessel 106 and receive power from anelectrical source coupled to the vessel 106 (e.g., through a cable,stand, or plate).

The vessel 106 may be any shape. In some embodiments, the sides of thevessel 106 form a polygon with any number of sides. For example, thesides of the vessel 106 may form a hexagon. All or some of the sides ofthe vessel 106 may be rounded or angular.

Although FIGS. 4-14 depict patterns of protrusions and indentations(e.g., ridges and furrows), the pattern of protrusions and indentationsmay not, or need not, be uniform. For example, a shaped surface maycomprise a random assortment of any shapes (e.g., a random assortment ofprotrusions and/or indentations) to increase surface area. In oneexample, the random assortment increases the surface area by at least1.2 times (or more) relative to the surface area of a flat surface. Inother examples, the random assortment increases the surface area by atleast 1.5 times or more, 2 times or more, 3 times or more, or the likerelative to the surface area of a flat surface. All or a part of asurface (e.g., base outer surface 302, base inner surface 304, wallouter surface 306, or wall inner surface 308) may comprise patterns,random assortments, or a combination of patterns and random assortmentsof shapes.

Further, although FIGS. 4-14 depict patterns of protrusions andindentations, the protrusions and/or indentations (e.g., ridges,furrows, corrugations, or the like) may include any number of geometricshapes or forms of any size or shape. Width, depth, and/or otherdefining measurement(s) of protrusions and/or indentations may vary overany trajectory and/or may vary with respect to other protrusions and/orindentations that are formed on the inner or outer surfaces of thekettle 106.

FIG. 4 is a planar view of an example shaped surface 400 that iscorrugated according to an example pattern. In various embodiments, allor a portion of the base inner surface 304, the base outer surface 302,the wall inner surface 308, an/or the wall outer surface 306, may beshaped according to at least a portion of the shaped surface 400 shownin FIG. 4.

The shaped surface 400 includes a plurality of ridges 402-1 . . . 402-n(hereinafter referred to as “ridges 402”) and furrows 404-1 . . . 404-n(hereinafter referred to as “furrows 404”). By including ridges 402 andfurrows 404, the surface area of the shaped surface 400 is increasedover the surface area of a flat surface having the same diameter 406that the shaped surface 400 has.

One or more of the ridges 402 may include portions that extend from thesurface and one or more of the furrows 404 may be the lowest portion(e.g., at the bottom or in the surface such as an indentation) of theshaped surface 400. In some embodiments, the shaped surface 400 has asurface area that is at least 1.2 times greater or more than if thebottom of the kettle was flat. In various embodiments, the shapedsurface 400 has a surface area that is at least two times greater thanif the shaped surface 400 was flat. In some embodiments, the shapedsurface 400 has a surface area that is at least three times greater thanif the bottom of the kettle 100 was flat. In some embodiments, theridges 402 and the furrows 404, in the example pattern shown in FIG. 4,are parallel to each other. In various embodiments, all or some of theridges 402 and the furrows 404 may, or may not, be parallel to eachother.

In some embodiments, adjacent ridges 402 and furrows 404 are shaped as asinusoidal wave. In being shaped as a sinusoidal wave, ridge sides ofthe ridges 402 are curved towards ridge top planes at the top of theridges 402. The ridge top plane is a hypothetical flat surface whichcontains the top of each ridge 402. For example, the ridge top plane maybe a tangential plane containing the peak (e.g., highest amplitudevalue) point of one, all, some, or most ridges 402. In some embodiments,the period, amplitude, phase angle, and/or symmetry of differentportions of any number of the sinusoidal waves may vary.

Additionally, in being shaped as a sinusoidal wave, furrow sides of thefurrows 404 are curved towards furrow bottom planes at the bottom of thefurrows 404. The furrow bottom plane is a hypothetical flat surfacewhich contains the bottom of each furrow 404. For example, the furrowbottom plane may be a tangential plane containing the trough (e.g.,lowest amplitude value) point of all, some, or most furrows 404.

In some embodiments, adjacent ridges 402 and furrows 404 are shaped as asquare wave. In being shaped as a square wave, the top portion of eachof the ridges 402 (e.g., highest amplitude value) may be in a tangentialplane (e.g., a ridge top plane). Similarly, bottom portions of each ofthe furrows 404 (e.g., lowest amplitude value) may be in a tangentialplane (e.g., a furrow bottom plane). In various embodiments, the period,amplitude, phase angle, and/or symmetry of any portion of any or all ofthe square waves may vary.

In various embodiments, regardless if the shaped portion is sinusoidal,is rectangular wave shaped, includes posts, includes protrusions,includes indentations, and/or the like, one, some, or all of the shapedportions (e.g., ridges 402) may have different heights (e.g., may havedifferent highest amplitude values) whereby not all of the peaks (e.g.,top portions) of the shaped portions may be in a plane. Similarly, one,some, or all of the shaped portions (e.g., furrows 404) may havedifferent troughs (e.g., may have different lowest amplitude values)whereby not all of the lowest point of the shaped portions may be in aplane. In various embodiments, symmetry of any or all of the shapedsurface (e.g., any or all of the posts, waves, protrusions, and/orindentations) may vary.

Although FIG. 4 depicts eighteen (18) parallel shaped portions 400,there may be any number of shaped portions that may be parallel,partially parallel, or not parallel. It will be appreciated that theremay be any number of shaped portions 400 (including high portions andlow portions of any shape or combination of shapes), and the shapedportions 400 may vary in their size(s).

FIG. 5 is a planar view of an example shaped surface 500 that iscorrugated according to another example pattern. In various embodiments,an applicable combination of all or a portion of a base inner surface,and all or a portion of a base outer surface may be shaped according tothe shaped surface 500 shown in FIG. 5.

The shaped surface 500 includes a plurality of ridges 502-1 . . . 502-n(hereinafter referred to as “ridges 502”) and furrows 504-1 . . . 504-n(hereinafter referred to as “furrows 504”). In including ridges 502 andfurrows 504, the surface area of the shaped surface 500 is increasedover a surface area of a flat surface of the same size as the shapedsurface 500. In some embodiments, the shaped surface 500 has a surfacearea that can be at least 1.2 times or greater than if the shapedsurface 500 was flat. In various embodiments, the shaped surface 500 hasa surface area that can be at least two times or greater than if theshaped surface 500 was flat. In another embodiment, the shaped surface500 has a surface area that can be at least three times or greater thanif the shaped surface 500 was flat.

The ridges 502 and the furrows 504 are arranged adjacent to each otherconcentrically about a pattern center 506 of the shaped surface 500. Thepattern center 506 can be the center of the base outer surface 302 orthe center of a base inner surface 304 depending on which surface of thebase is patterned according to the shaped surface 500 shown in FIG. 5.In some embodiments, one or more pattern center(s) 506 may originateanywhere on the base outer surface 302, the base inner surface 304, wallouter surface 306, and/or wall inner surface 308.

In some embodiments, the ridges 502 and the furrows 504 can be shaped asa sinusoidal wave, as discussed with respect to FIG. 4. In anotherembodiment, the ridges 502 and the furrows 504 can be shaped as a squarewave, as discussed above with respect to FIG. 4.

Although FIG. 5 depicts ten (10) concentric circles, there may be anynumber of concentric circles or partially concentric circles. It will beappreciated that there may be any number of shaped portions (includinghigh portions and low portions of any shape or combination of shapes),and the shaped portions may vary in their size(s).

FIG. 6 is a planar view of an example shaped surface 600 that iscorrugated according to another example pattern. In various embodiments,an applicable combination of all or a portion of a base inner surfaceand/or all or a portion of a base outer surface may be shaped accordingto the shaped surface 600 shown in FIG. 6.

The shaped surface 600 includes a plurality of ridges 602-1 . . . 602-n(hereinafter referred to as “ridges 602”) and furrows 604-1 . . . 604-n(hereinafter referred to as “furrows 604”). In including ridges 602 andfurrows 604, the surface area of the shaped surface 600 is increasedover a surface area of a flat surface of the same size as the shapedsurface 600. In some embodiments, the shaped surface 600 has a surfacearea that can be at least 1.2 times or greater than if the shapedsurface 600 was flat. In another embodiment, the shaped surface 600 hasa surface area that can be at least two times or greater than if theshaped surface 600 was flat. In another embodiment, the shaped surface600 has a surface area that can be at least three times or greater thanif the shaped surface 600 was flat. The ridges 602 and the furrows 604radiate out from a pattern center 606. The pattern center 606 can be thecenter, or originate at one or more points distant from the center, ofthe base outer surface 302 or the base inner surface 304 depending onwhich surface of the base is patterned according to the shaped surface600 shown in FIG. 6. In the pattern shown in FIG. 6, the furrows 604increase in furrow width 608 as the furrow extends out from the patterncenter 606. In other embodiments, a ridge width of a ridge can increaseas the ridge extends out from the pattern center 606.

In various embodiments, different patterns may include different patterncenters any of which may be different than the center of a bottom outersurface 302 and/or the center of a bottom inner surface 304 (e.g.,pattern center 606 in FIG. 6). For example, a bottom outer surface 302may include any number of pattern centers located next to each other,each pattern center including its own center. Any number of shapedsurfaces may be oriented in any manner. As a result, each pattern and/orcombination of patterns of shaped surfaces may be oriented around anynumber of pattern centers.

In some embodiments, the ridges 602 and furrows 604 can be shaped as asinusoidal wave, as discussed with respect to FIG. 4. In variousembodiments, the ridges 602 and furrows 604 may be shaped as halfcircles. In another embodiment, the ridges 602 and the furrows 604 canbe shaped as a square wave, as discussed with respect to FIG. 4.

Although FIG. 6 depicts twenty four (24) shaped portions radiating froma center, there may be any number of shaped portions radiating form thecenter. It will be appreciated that there may be any number of shapedportions (including high portions and low portions of any shape orcombination of shapes), and the shaped portions may vary in theirsize(s).

FIG. 7A is a cross-sectional view of a shaped surface 700 that includesridges 702 and furrows 704 shaped according to a sinusoidal wave. Theshaped surface 700 shown in FIG. 7A can be formed in accordance with theexample patterns shown in FIGS. 4-6. The shaped surface 700 can beformed on any combination of a base inner surface 304, a base outersurface 302, a wall inner surface 308, and a wall outer surface 306. Insome embodiments, the shaped surface 700 shown in FIG. 7A has at least 2times greater surface area (e.g., at least 2.3 times greater surfacearea) than the surface area of a flat surface.

The ridges 702 include ridge sides 706 that are curved towards a ridgetop plane 708 (e.g., a plane tangent to the peaks of the sinusoidalwaves). In an embodiment, the ridges 702 can be shaped such that a crosssection of a ridge of the ridges 702 exhibits reflection symmetry abouta ridge axis of symmetry 710 that is normal to the ridge top plane 708.

The furrows 704 include furrow sides 712 that are curved towards afurrow bottom plane 714 (e.g., a plane tangent to the troughs of thesinusoidal waves). In an embodiment, the furrows 704 can be shaped suchthat a cross section of a furrow of the furrows 704 exhibits reflectionsymmetry about a furrow axis of symmetry 716 that is normal to thefurrow bottom plane 714.

An example function of heat transfer is as follows, where “U” is theheat transfer coefficient, “Area” is the area for which the heat istransferred to the substance, and “ΔT” is the difference in temperature(e.g., between a solid surface such as a portion of the kettle 100 and acontained liquid):Q=(U)(Area)(ΔT)Here, “Q” has units of energy per time (e.g., Joules per second).

In various embodiments, an arc length for a sinusoidal wave is definedas follows. Assuming the sinusoidal wave includes component a, wherea=peak amplitude (measured from the zero crossings) and 2π/b=period ofthe sinusoidal wave:

     y = a  sin   bx$\mspace{76mu}{\frac{dy}{dx} = {{ab}\mspace{14mu}\cos\mspace{14mu}{bx}}}$${{Arc}\mspace{14mu}{length}} = {S = {{2{\int_{0}^{\frac{\pi}{b}}{\sqrt{1 + \left( \frac{dy}{dx} \right)^{2}}{dx}}}} = {S = {2{\int_{0}^{\frac{\pi}{b}}{\sqrt{1 + {a^{2}b^{2}{\cos^{2}({bx})}}}{dx}}}}}}}$     Assuming  a = π  and  b = 1  then:$\mspace{76mu}{S = {2{\int_{0}^{\pi}{\sqrt{1 + {\pi^{2}{\cos^{2}(x)}}}{dx}}}}}$     S = 2(7.21403) = 14.482Assuming unit width, the area equals (S)(1) or S.

FIG. 7B is a cross-sectional view of a shaped surface 750 that iscorrugated with ridges 702 and furrows 704 shaped according to a squarewave. The shaped surface 750 shown in FIG. 7B can be formed inaccordance with the example patterns shown in FIGS. 4-6. The shapedsurface 750 can be formed on any combination of a base inner surface304, a base outer surface 302, a wall inner surface 308, and a wallouter surface 306. In some embodiments, the shaped surface 750 shown inFIG. 7B has at least 3 times greater surface area than a surface area ofa flat surface.

The ridges 702 include planar tops that form the tops of the ridges 702.The ridges 702 include ridge sides 706 that extend linearly upwardstowards a ridge top plane 708. The ridge top plane 708 is formed along aplanar top of a ridge with a corresponding ridge side 706 that extendslinearly upwards towards the ridge top plane 708.

The furrows 704 include planar bottom that form the bottoms of thefurrows 704. The furrows 704 include furrow sides 712 that extendlinearly downwards towards a furrow bottom plane 714. The furrow bottomplane 714 is formed along a planar bottom of a furrow with acorresponding furrow side 712 that extends linearly downward towards thefurrow bottom plane 714.

In various embodiments, a rectangular wave pattern is as follows.Assuming the rectangular wave includes component a where a is the peakamplitude (e.g., the height measured from the zero crossings) and b isthe width of a rectangular wave (e.g., as measured along the zerocrossings):

-   -   S=4a+2b    -   If a=b=π, S=4π+2π=6π=18.85    -   Relative to a flat surface with length    -   2b=2π=6.2832

Assuming unit width, the area equals (S)(1) or S.

For example:

Area (Assuming Area Relative to Surface Unit Width) a Flat Surface Flat6.2832 1.000 Sinusoidal in one dimension 14.482 2.305 with amplitudedefined above equal to half of the period Rectangular in one dimension18.85 3.000 with amplitude defined above equal to half of the period

FIG. 8 is a planar view of a shaped surface 800 that is corrugatedaccording to another example pattern. In various embodiments, anapplicable combination of a portion of a base inner surface 304, a baseouter surface 302, a wall inner surface 308, and a wall outer surface306 may be shaped according to the shaped surface 800 shown in FIG. 8.

The shaped surface 800 includes a plurality of ridges 802-1 . . . 802-n(hereinafter referred to as “ridges 802”) and furrows 804-1 . . . 804-n(hereinafter referred to as “furrows 804”). By including ridges 802 andfurrows 804, the surface area of the shaped surface 800 is increasedrelative to the surface area of a flat surface of a same size as theshaped surface 800. In some embodiments, the shaped surface 800 has asurface area that is at least 1.2 times greater than if the shapedsurface 800 was flat. In another embodiment, the shaped surface 800 hasa surface area that is at least two times greater than if the shapedsurface 800 was flat. In another embodiment, the shaped surface 500 hasa surface area that can be at least three times or greater than if theshaped surface 500 was flat. The ridges 802 are shaped along thelongitudinal length of the ridges 802 according to a planar square wavepattern. Similarly, the furrows 804 are shaped along the longitudinallength of the furrows according to an inverse of a planar square wavepattern of which the ridges 802 adjacent to the furrows 804 are shaped.

FIG. 9 is a planar view of a shaped surface 900 that is corrugatedaccording to another example pattern. In various embodiments, anapplicable combination of a portion of a base inner surface 304, a baseouter surface 302, a wall inner surface 308, and a wall outer surface306 may be shaped according to the shaped surface 900 shown in FIG. 9.

The shaped surface 900 includes a plurality of ridges 902-1 . . . 902-n(hereinafter referred to as “ridges 902”) and furrows 904-1 . . . 904-n(hereinafter referred to as “furrows 904”). In including ridges 902 andfurrows 904, the surface area of the shaped surface 900 is increasedover a surface area of a flat surface of a same size as the shapedsurface 900. In some embodiments, the shaped surface 900 has a surfacearea that is at least 1.2 times greater than if the shaped surface 900was flat. In some embodiments, the shaped surface 900 has a surface areathat is at least two times greater than if the shaped surface 900 wasflat. In another embodiment, the shaped surface 900 has a surface areathat is at least three times greater than if the shaped surface 900 wasflat. The ridges 902 are shaped along the longitudinal length of theridges 902 according to a planar sinusoidal pattern. Similarly, thefurrows 904 are shaped along the longitudinal length of the furrowsaccording to an inverse of a planar sinusoidal wave pattern of which theridges 902 adjacent to the furrows 904 are shaped.

FIG. 10 is a planar view of a shaped surface 1000 with a plurality ofprotrusions according to a protrusion pattern. In various embodiments,protrusions included in the protrusion pattern of the shaped surfaceshown in FIG. 10 can include any combination of square shapedprotrusions, trapezoid shaped protrusions, triangular shapedprotrusions, sinusoidal shaped protrusions, and/or protrusions of anyshape or pattern.

The protrusion pattern shown in FIG. 10 includes protrusion lines 1002-1. . . 1002-n (hereinafter referred to as “protrusion lines 1002”), inwhich protrusions are formed to increase the surface area of the shapedsurface 1000. In the shaped surface shown in FIG. 10, the protrusionlines 1002 are parallel to each other.

FIG. 11 is a planar view of a shaped surface 1100 with a plurality orprotrusions according to another protrusion pattern. In variousembodiments, protrusions included in the protrusion pattern of theshaped surface shown in FIG. 11 can include any combination of squareshaped protrusions, trapezoid shaped protrusions, sinusoidal shapedprotrusions, and/or protrusions of any shape or pattern.

The protrusion pattern shown in FIG. 11 includes protrusion columns1102-1 . . . 1102-n (hereinafter referred to as “protrusion columns1102”) and protrusion rows 1104-1 . . . 1104-n (hereinafter referred toas “protrusion rows 1104”). Protrusions are formed within the protrusioncolumns 1102 and the protrusion rows 1104 to increase the surface areaof the shaped surface 1100. The protrusion columns 1102 and theprotrusion rows 1104 intersect to form an array of protrusions on theshaped surface 1100.

FIG. 12 is a planar view of a shaped surface 1200 with a plurality orprotrusions according to another protrusion pattern. In variousembodiments, protrusions included in the protrusion pattern of theshaped surface shown in FIG. 12 can include any combination of squareshaped protrusions, trapezoid shaped protrusions, sinusoidal shapedprotrusions, and/or protrusions of any shape or pattern.

The protrusion pattern shown in FIG. 12 includes protrusion rings 1202-1. . . 1202-n (hereinafter referred to as “protrusion rings 1202”)concentrically formed about a pattern center 1204 of the shaped surface1200. The pattern center 1204 can be a center of the base outer surface302 or the center of a base inner surface 304 depending on which surfaceof the base is patterned according to the shaped surface 1200 shown inFIG. 12. Protrusions are formed within the protrusion rings 1202 toincrease the surface area of the shaped surface 1200.

In various embodiments, different protrusion patterns (including, forexample, the protrusion pattern shown in FIG. 12) may include one ormore different pattern centers, any of which may be different than thecenter of a bottom outer surface 302 and/or the center of a bottom innersurface 304. For example, a bottom outer surface 302 may include anynumber of pattern centers located next to each other, each patterncenter including its own center. Any number of shaped surfaces may beoriented in any manner. As a result, each pattern and/or combination ofpatterns of a shaped surface may be oriented around any number ofpattern centers.

FIG. 13 is a planar view of a shaped surface 1300 with a plurality orprotrusions according to another protrusion pattern. In variousembodiments, protrusions included in the protrusion pattern of theshaped surface shown in FIG. 13 can include any combination of squareshaped protrusions, trapezoid shaped protrusions, sinusoidal shapedprotrusions, and/or protrusions of any shape or pattern.

The protrusion pattern shown in FIG. 13 includes protrusion radials1302-1 . . . 1302-n (hereinafter referred to as “protrusion radials1302”) formed to radiate out from a pattern center 1304, center area, orother focal points or areas, of the shaped surface 1300. The patterncenter 1304 can be a center of the base outer surface 302 or the centerof a base inner surface 304 depending on which surface of the base ispatterned according to the shaped surface 1300 shown in FIG. 13.Protrusions are formed within the protrusion radials 1302 to increasethe surface area of the shaped surface 1300. The protrusion radials 1302have protrusion radial widths 1306 that can be constant along the lengthof the protrusion radials 1302, or they can change along the length ofthe protrusion radials 1302. For example, protrusion radial widths 1306of the protrusion radials 1302 can increase along the length of theprotrusion radials 1302 as the protrusion radials 1302 extend out fromthe pattern center 1304.

In various embodiments, different protrusion patterns (including, forexample, the protrusion pattern shown in FIG. 13) may include differentpattern centers any of which may be different than the center of abottom outer surface 302 and/or the center of a bottom inner surface304. For example, a bottom outer surface 302 may include any number ofpattern centers located next to each other, each pattern centerincluding its own center.

FIG. 14A is a cross-sectional view of a shaped surface 1400 withprotrusions 1402 shaped as a sinusoidal wave. In various embodiments,the protrusions 1402 shown in FIG. 14A can be arranged in the protrusionpatterns shown in FIGS. 10-13.

In being shaped as a sinusoidal wave, the protrusions 1402 haveprotrusion sides 1404 that curve upwards towards a protrusion plane1406. The protrusion plane 1406 is a plane formed across the tops (e.g.,peaks) of the protrusions 1402 at a protrusion height 1408 of theprotrusions 1402. In the shaped surface 1400 shown in FIG. 14A, theprotrusions 1402 all have the same protrusion height 1408. Theprotrusion cross-section of the protrusions 1402 exhibit reflectionsymmetry about a protrusion axis of symmetry 1410 normal to theprotrusion plane 1406.

FIG. 14B is a cross-sectional view of a shaped surface 1450 withprotrusions 1452 shaped as a square wave. In various embodiments, theprotrusions 1452 shown in FIG. 14B can be arranged in the protrusionpatterns shown in FIGS. 10-13.

In being shaped as a square wave, the protrusions 1452 have protrusionsides 1454 that extend upwards towards a protrusion plane 1456. Theprotrusion plane 1456 is a plane formed across the top portions (e.g.,peaks) of the protrusions 1452 at a protrusion height 1458 of theprotrusions 1452. In the shaped surface 1450 shown in FIG. 14B, theprotrusions 1452 all have the same protrusion height 1458.

The shaped portions (e.g., protrusions and/or indentations) may compriseany materials including, but not limited to, an alloy, a ceramic, ametal, or any combination of any materials. In some embodiments, shapedportions may include a sandwich structure of various layers ofmaterials.

In various embodiments, any or all of the shaped portions may includethe same material as all or a part of the base of a vessel. In someembodiments, any or all of the shaped portions are of a differentmaterial as all or a part of the base of a vessel.

FIGS. 15A-G depict a variety of different protrusions and/orindentations that may be on the outer base of a vessel, inside thevessel, or on both the outer base and inside the vessel (e.g., baseinner surface 304 and base outer surface 302). In some embodiments,there may be any combination of one or more different shapes (e.g., oneor more in any combination of protrusions and/or indentations). Forexample, a bottom of a vessel may include conical protrusions as well asconical or triangular indentations on the bottom of the vessel.

FIG. 15A depicts interlocking elbow shaped surfaces in some embodiments.In various embodiments, the interlocking elbow shaped surfaces mayproject outward forming at least one protrusion from the base of thekettle (i.e., toward the outside of the kettle). In various embodiments,the elbow shaped surfaces may project inward (forming at least oneindentation) from the base of the kettle (i.e., toward the inside of thekettle). A kettle may include any combination of projections andindentations. It will be appreciated that any shape, form, size, or anycombination of shapes, forms, and sizes may be used for protrusionsand/or indentations.

FIG. 15B depicts conical shaped protrusions in some embodiments. FIG.15C depicts conical shaped indentations in some embodiments. FIG. 15Ddepicts triangular shaped protrusions in some embodiments. FIG. 15Edepicts triangular shaped indentations in some embodiments. FIG. 15Fdepicts dimple shaped indentations in some embodiments. FIG. 15G depictsdimple shaped protrusions in some embodiments. In FIG. 15B-G, theprotrusions extend toward, and the indentations extend away from, thetop of the page on which they are depicted.

Although the shaped protrusions and indentations in FIG. 15B-G appear tobe the same shape, size, height, symmetry, or the like, they may bedifferent for any number of the shaped protrusions and/or shapedindentations. Further, there may be any amount of space between theshaped protrusions and/or indentations. Moreover, although theprotrusions and/or indentations appear to be right next to each other,the protrusions and/or indentations may be spaced in any way or in anypattern.

In various embodiments, fluid inside the vessel (e.g., the kettle 100 ofFIG. 1) may undergo movement caused by convection. Convection may becharacterized by movement within the fluid caused at least in part bythe tendency of hotter and therefore less dense portions of the fluid(and/or material in the fluid) to rise while colder, denser portions ofthe fluid (and/or material in the fluid) move downward. Convection maybe caused by non-uniform heating. Convection in a plane horizontal to alayer of fluid heated from one side (e.g., below) may be termedRayleigh-Benard convection.

In the prior art, kettles and other cooking vessels celebrate thefeature of uniform heating. While uniform heating may keep a solid in apan (e.g., a steak) from cooking unevenly, convection in a fluid mayenhance heat transfer to a fluid contained in the vessel, therebyallowing fluids (e.g., water, liquid, substance, or liquid/solidmixtures) to heat more quickly. Further, the fluid motion due toconvection may facilitate mixing of the fluid.

Convection may be caused (e.g., induced) in any number of ways. In someembodiments, there may be variations in the thickness of the base orwalls of the vessel which may cause convection. For example, with regardto FIG. 3, one section of a base portion may be thicker than anothersection of the base portion. Similarly, one section of a wall portionmay be thicker than another section of the wall portion. In one example,a vessel may have a thicker base at the periphery and a thinner base atthe center. In another example, the base portion may include a pluralityof portions (e.g., a pattern) that are thicker than other portions ofthe base (e.g., a pattern of thicker portions in all or a section of thebase portion). Similarly and/or in addition, the wall portion mayinclude a plurality of portions (e.g., a pattern) that are thicker thanother portions of the wall (e.g., a pattern of thicker portions in allor a section of the wall portion). The variations in thickness maycreate uneven heating such that may cause convection.

In various embodiments, the base portion may be thicker in some areasand thinner in others. For example, a vessel may have a thicker base atthe periphery and a thinner base at the center (e.g., an inverted coneon the base outer surface 302 or the base inner surface 304). It will beappreciated that, in some embodiments, the base portion may be thinnerin some areas and thicker in others (e.g., a cone shape). Base portionsin these configurations may contribute to convection.

In some embodiments, the thickness of the base portion may beconsistent, but convection may be caused by including differentmaterials within the base 102 and/or walls 104 of the vessel 106. Asdiscussed herein, the vessel 106 may, for example, include a core of onemetal (e.g., aluminum) clad in stainless steel or other non-reactivemetal(s) or alloy(s), and the base of the vessel may have sections of acore that are thicker than other portions (e.g., some portions of thecore may be thicker aluminum or copper than other portions of the core).The variations in thickness of the core and variations in the amount ofmaterial with different thermal properties (discussed further herein)may create uneven heating such that convection may be induced.

There may be any number of different materials in the base and/or wallsof the vessel that may cause convection. For example, differentmaterials may be utilized that have different thermal properties. Thedifferent material can be included in some portions (i.e., not all) ofthe base (e.g., the base may include stripes, squares, chunks, bits orother portions of different materials with different thermal propertiesthan the material which is included in the rest of the base) so as toinduce convection. It will be appreciated that highly heat conductivematerials may be included (e.g., copper or aluminum) and/or heatinsulating materials can be included in the base or walls of the vessel.

For example, the sides and/or base of a vessel may include materials ofdifferent thermal characteristics (e.g., with different thermaldiffusivities). In some embodiments, the sides and/or base of the vesselmay include either exposed (e.g., on the base inner surface 304 of thevessel) or clad (e.g., within a core) strips of material that aredifferent (e.g., the strips may be of aluminum and the rest of the basemay be stainless steel). There may be any pattern of strips or materialsof any shapes within (or on) the base inner surface 304, base outersurface 302, wall inner surface 308, and/or wall outer surface 306 ofthe vessel. In another example, any or all of the shaped surfaces (seeFIGS. 4, 10, and 11) may comprise different materials than all or partsof the base and/or walls of the vessel.

It will be appreciated that a vessel may include variations in thicknessand/or different materials.

Differences in surface area at the base 102 and/or walls 104 of a vessel106 between a thermal energy source and fluid (e.g., the base outersurface 302 of a vessel 106 or a base inner surface 304 of the vessel106) may cause convection of fluid within the vessel 106. As discussedherein, the shaped portion of the wall outer surface 306 and/or theshaped portion of the wall inner surface 308 may include, for example,raised sinusoidal ridges, raised rectangular ridges, indented sinusoidalfurrows, indented rectangular ridges, posts, raised portions, depressedportions, protrusions, indentations, or the like of any size or shape.The shaped portion may include raised portions of a surface, depressionsin the surface, or a combination of raised portions and depressedportions (e.g., a combination of protrusions and indentations) of thesurface. Examples include, but are not limited to, shaped portions with(e.g., substantially) increased surface area (in comparison with a flatsurface). In various embodiments, only a portion or the entire wallouter surface 306 and/or at least a portion of the wall inner surface308 includes a shaped portion.

As previously discussed, differences in surface area across the base 102or walls 104 of a vessel 106 between a thermal energy source and fluid(e.g., the base outer surface 302 of a vessel 106 or a base innersurface 304 of the vessel 106) may cause (e.g., induce) convection offluid within the vessel 106. For example, differences in surface area ofridges and/or furrows (e.g., changes in surface area of the protrusionsand/or indentations) of the base outer surface 302 of a vessel 106 maycause heat transfer to be non-uniform, thereby causing convection (e.g.,motion) of the fluid inside the vessel 106 as well as increases in heattransfer.

In various embodiments, differences in surface area of all or some ofthe base or walls of the vessel 106 may increase, by convection, therate at which thermal energy is transferred to a substance (e.g., fluid)contained within the vessel 106. The increased rate of thermal energytransfer may be substantially increased when compared to vessels in theprior art (e.g., with less surface area and/or uniform constructionwhich do not induce convection). Further, the convection induced by thedifferences in surface area may further cause mixing of the substancewithin the vessel 106.

FIG. 16A is a cross-sectional view of a shaped surface 1600 with roundedprotrusions 1602. In various embodiments, the protrusions 1602 shown inFIG. 16A can be arranged in the protrusion patterns shown in FIGS.10-13.

The rounded protrusions 1602 may be shaped as waves. The protrusions1602 may have different amplitudes (e.g., heights) as depicted in FIG.16A or may have heights in any pattern. In some embodiments, theprotrusions 1602 have protrusion sides 1604 that are directed upwardstowards protrusion planes 1606-1616. The protrusion planes 1606-1616 areplanes that are formed across the tops (e.g., peaks) of the protrusions1602.

In the shaped surface 1600 shown in FIG. 16A, the protrusions 1602 havea pattern of protrusion heights that are higher at the periphery andshorter at the center. It will be appreciated that the protrusionheights may be random or may be of any pattern. For example, protrusionheights may be shorter at the periphery and higher at the center. Inanother example, each protrusion may be higher or shorter than anadjacent protrusion (e.g., taller protrusions may be next to shorterprotrusions).

It will also be appreciated that there may be any number of patternedshapes on each vessel (e.g., on the outer surface 302 or the base innersurface 304). For example, there may be any number of circular patternsof protrusions on the base of a vessel. For example, each circularpattern may include protrusions like those depicted in FIG. 16A (e.g.,shorter at the center and higher at the periphery of each circularpattern). As similarly discussed, the circular pattern of protrusionsmay be higher in the center and lower at the periphery of each circularpattern. A circular pattern may be asymmetric. In some embodiments,circular patterns across the base of a vessel may have differentprotrusions, different patterns, different size, and/or different shape.Similarly, there may be a combination of circular, rectangular, and/orsquare patterns (or patterns of any shape) on the base outer surface 302or the base inner surface 304.

FIG. 16B is a cross-sectional view of a shaped surface 1650 withprotrusions 1652 shaped as a square wave. In various embodiments, theprotrusions 1652 shown in FIG. 16B can be arranged in the protrusionpatterns shown in FIGS. 10-13.

In being shaped as a square wave, the protrusions 1652 have protrusionsides 1654 that extend upwards towards one of protrusion planes 1656,1658, 1660, 1662, 1664, and 1666. The protrusion planes 1656-1666 areplanes that are formed across the top portions (e.g., peaks) of theprotrusions 1652.

As similarly discussed regarding the shaped surface 1600 shown in FIG.16A, the protrusions 1652 have a pattern of protrusion heights that arehigher at the periphery and shorter at the center. It will beappreciated that the protrusion heights may be random or may be of anypattern. For example, protrusion heights may be shorter at the peripheryand higher at the center. In another example, each protrusion may behigher or shorter than an adjacent protrusion (e.g., taller protrusionsmay be next to shorter protrusions).

It will be appreciated that the variety of different protrusions and/orindentations depicted in FIGS. 15A-G may have sections of protrusionsand/or indentations with different surface area than other sections ofprotrusions and/or indentations. Differences in surface area and/ormaterials (e.g., with different thermal diffusion properties) maypromote non-uniform heating and induce convection. The variety ofdifferent protrusions and/or indentations depicted in FIGS. 15A-G may beon the outer base of a vessel, on the inner base of a vessel, on theinner wall of a vessel, and/or on the outer wall of a vessel. In variousembodiments, the variety of different protrusions and/or indentationsdepicted in FIGS. 15A-G may be on the base inner surface 304 and thebase outer surface 302). In some embodiments, there may be anycombination of one or more different shapes (e.g., one or more in anycombination of protrusions and/or indentations). For example, a bottomof a vessel may include conical protrusions as well as conical ortriangular indentations in the bottom of the vessel.

It will also be appreciated that there may be multiple patterned shapeson the inside and/or the outside of the vessel. For example, there maybe any number of square or circular patterns of protrusions on the baseouter surface 302 or the base inner surface 304. For example, eachcircular pattern may include protrusions like those depicted in FIG. 16B(e.g., shorter at the center and higher at the periphery of eachcircular pattern). As similarly discussed, the circular pattern ofprotrusions may be higher in the center and lower at the periphery ofeach circular pattern. A circular pattern may be asymmetric. In someembodiments, circular patterns across the base of a vessel may havedifferent protrusions, different patterns, and/or be of any size and/orshape. Similarly, there may be a combination of circular, rectangular,and/or square patterns (or patterns, sizes, or any shape) on the base ofthe outer surface 302 or the base inner surface 304.

In various embodiments, the shaped portion of the base outer surface302, base inner surface 304, wall outer surface 306, and/or wall innersurface 308 is shaped to have 1.2 or more times (e.g., 1.5 times ormore, 2 times or more, 3 times or more, or the like) the surface areathan its corresponding flat surface. Further, sections of the baseportion(s) may have different surface area(s) than other sections of thebase portion(s), thereby further inducing convection.

In various embodiments, the shaped portions may comprise differentmaterials that induce and/or further contribute to non-uniform heatingand convection. The shaped portions (e.g., protrusions and/orindentations) may comprise any material or the like including, but notlimited to an alloy, a ceramic, a metal, or any combination of anymaterials. In some embodiments, shaped portions may include a sandwichstructure of various layers of materials. In various embodiments, any orall of the shaped portions are of the same material as all or a part ofthe base of a vessel. In some embodiments, any or all of the shapedportions are of a different material as all or a part of the base of avessel.

In various embodiments, the vessel may include a mechanical mixer whichmay mix fluids in the vessel and force convection. For example, theremay be one or more mixers (e.g., a blade or a propeller driven by amotor with a power source such as a battery) attached to the base, top,receiving aperture, or walls inside the vessel.

FIG. 17 is a planar view of a shaped surface 1700 with a plurality ofprotrusions according to another protrusion pattern. The protrusionsincluded in the protrusion pattern of the shaped surface shown in FIG.17 may include different protrusions with different surface areas.Further, the protrusions may comprise different material(s) from eachother and/or the base of the vessel.

In various embodiments, protrusions included in the protrusion patternof the shaped surface shown in FIG. 17 can include any combination ofsquare shaped protrusions, trapezoid shaped protrusions, and sinusoidalshaped protrusions. Each square shaped protrusion, trapezoid shapeprotrusion, and sinusoidal shaped protrusion included in the shapedsurface shown in FIG. 17 can be formed around a central protrusion axisfor each protrusion.

The protrusion pattern shown in FIG. 17 includes protrusion radials1702-1 . . . 1702-n (hereinafter referred to as “protrusion radials1702”) formed to radiate out from a pattern center 1704 along centralspines to create a star pattern of the shaped surface 1700. The patterncenter 1704 can be a center of the base outer surface, or the center ofa base inner surface, depending on which surface of the base ispatterned according to the shaped surface 1700 shown in FIG. 1700.Protrusions are formed within the protrusion radials 1702 to increasethe surface area and/or provide differences in surface area of theshaped surface 1700. The protrusion radials 1702 have protrusion radialwidths 1706 that can be constant across the length of the protrusionradials 1702 or can change along the length of the protrusion radials1702. For example, protrusion radial widths 1706 of the protrusionradials 1702 can increase along the length of the protrusion radials1702 as the protrusion radials 1702 extend out from the pattern center1704.

It will be appreciated that the bottom outer surface 302 of the kettleand/or an inside surface (e.g., bottom inner surface 304) may includeany shape of ridges, furrows, protrusions, indentations, and/or the likein any pattern that increases (e.g., substantially) surface area. Ifthere is a substantial increase in surface area between the outsidebottom surface of the kettle and a thermal source, the kettle may absorbheat at a substantially higher rate. If there is a substantial increasein surface area between the inside bottom surface of the kettle and aliquid in the kettle, then the kettle may transfer heat from the kettleto an enclosed substance or liquid at a substantially higher rate.

Changes in surface area may also induce convection. As a result, thetransfer of, or the rate of transfer of, heat from the vessel to anenclosed substance or liquid may occur at a substantially higher rate.Further, the induced convection may mix the substance or liquid, and maylead to more rapid heating of a substance or liquid contained in thevessel.

As a fluid within the vessel heats, convection currents can form, andtemperature-dependent physical properties (e.g., density, surfacetension, and kinematic viscosity) can induce convection currents havingcharacteristic patterns (e.g., 2-dimensional rolls or hexagonal cells).These convection currents induce mixing, and lead to more rapid heatingof a fluid contained in the vessel.

It will be appreciated that a horizontal layer of convecting fluid mayexhibit self-organizing (e.g., pattern-forming) properties. For example,depending on the fluid and non-uniform heating, toroidal vortices mayresult (e.g., because of the instability of differentially rotatingfluid and convection rolls).

In various embodiments, convection of fluid within the vessel maygenerate convective flow structures within the fluid. A flow structuremay depend, for example, upon surface tension of the fluid, nature ofheat transfer, variations in non-uniform heating, protrusions and/orindentations or indentations on the base and or walls of the vessel, andshape of the vessel. In one example, flow patterns may include polygonal(e.g., hexagonal) cells with upflow at the center of each cell anddownflow at the periphery. The pattern, for example, may resemble ahoneycomb pattern of individual cells. In some embodiments, convectioncan lead to a variety of flow patterns, all of which lead to higheroverall heat transfer, or a higher rate of heat transfer, to the fluidas a result of fluid motion and possible mixing.

It will be appreciated that convection patterns of quasi-two-dimensionalrolls or three-dimensional cells may appear in the fluid. The structureof thermogravitational (buoyancy-driven) convection may differ fromthermocapillary (surface tension-driven) convection.

The configuration of a cell in projection onto a plane (e.g., x and ycoordinate plane) is called the cell planform. FIG. 18A is a planformschematic diagram of two-dimensional rolls of convection cells. Sincethe wavevector is oriented in the x-direction, such rolls (parallel tothe y-axis) may be identified as “x-rolls.” In the vicinity of theinterface between two such rolls, the fluid may circulate in the x,yplane in opposite directions.

FIG. 18B is a planform schematic diagram of hexagonal L- and G-cells.This system may be a superposition of three roll sets with wavevectorshaving the same modulus and directed at an angel of 2π/3 to each other.A hexagonal cell may be identified as an L- or a G-cell depending on thesign of the velocity (e.g., on whether the fluid ascends or descends inthe central part of the cell). It will be appreciated that very smallalterations in the physical conditions, or small variations in thephysical properties of the fluid, can result in radical changes in thestructure of convection patterns.

Although G-cell formations may be more common in observed gases andL-cells may be more common in observed liquids, all or portions of thefluid in the vessel 106 may include one or more L-cells and/or G-cells.Direction and circulation may depend upon the derivatives of viscosityor density with temperature. It will be appreciated that ascending fluidin a convection cell may be warmer than the descending fluid. As aresult, the central part of the L-cell may be less viscous or less densefor liquids and the peripheral part of a G-cell may be less viscous orless dense for gases.

There may be transitions of patterns in a fluid of the vessel 106. Forexample, all or a portion of the fluid may start in a motionless stateand transition to a pattern of hexagonal cells. All or part of the fluidmay transition from a pattern of hexagonal cells to a pattern of rolls.Any or all transitions may be related to the density and/or theviscosity of all or a portion of the liquid and/or temperature (e.g.,depending on heat transfer).

FIG. 19 is a two-armed spiral in a fluid that rotates clockwise in someembodiments. It will be appreciated that variation(s) of one or morecharacteristics of the fluid with temperature may play a role in fluidrotation or convection, such as the variation of density and/orviscosity with temperature. Dependencies may be based on kinematicviscosity, thermal conductivity, and/or heat at constant pressure.Transitions (e.g., to the two-armed spiral or the like) may begin closerto the walls of the vessel and subsequently involve regions closer tothe center. For example, a roll pattern may be ordered into a left- orright-handed spiral with the number of arms varying from run to run. Theouter part of such a pattern may comprise concentric circular rolls.Each arm of the spiral may terminate in a pattern defect called adislocation and, as a result, the spiral may be mismatched with outerrings (see dislocations 1902 and 1904 in FIG. 9). The direction ofspiral rotation may be the result of waves propagating from the spiralcore (e.g., from the center of the vessel 106). The formation of a“global” spiral pattern fitting into container geometry may be an effectof a small horizontal temperature gradient near the wall of the vessel(e.g., producing sidewall forcing).

It will be appreciated that if the fluid layer has an appreciableasymmetry of the physical condition with respect to the midplane (e.g.,z=½ or an up-down asymmetry), then three-dimensional cells may form. If,however, the layer is symmetric, then two-dimensional rolls may arise. Atransition from some roll set to a mirror reflection about the midplanemay be equivalent to a uniform translation of the entire pattern in thedirection of a vector. Three-dimensional cells may not share thisproperty. It is therefore not surprising that rolls may be typical forthe case where the top and bottom part of a layer are indistinguishable.Alternately, the existence of hexagonal L- and G-cells is compatiblewith the presence of non-uniformity of viscosity (e.g., the direction ofcirculating may be such that the viscosity is minimum in the region ofthe highest strain rates which may be in the central part of a cell).

It will be appreciated that there may be no convection pattern, thatconvection patterns appear or disappear over time, and/or convectionpatterns change based on changes in heat transfer, variations orfluctuations in localized temperatures, and fluid characteristics.

FIG. 20A and FIG. 20B are roll patterns with boundaries of the rollsdepicted by dotted and solid lines. FIG. 20A depicts texture in arectangular container (the neighborhoods of the short container wallsare not visible). FIG. 20B depicts a schematic image of a texture in acircular container (dashed lines indicate the main features of thestructure of the large scale flow). As depicted in FIGS. 20A and B,there may be a tendency of rolls to approach the sidewalls at a rightangle.

In various embodiments, if there are no complicating factors, roll flowsmay represent a basic form of steady-state convection. It will beappreciated that rolls are typically not quite straight and the rollflow may not be strictly two-dimensional. This may be due, at least inpart, because the flow involves only a portion of a layer and thepresence of sidewalls may considerably affect the flow of the fluid andits structure.

It will be appreciated that flows within a fluid may be affected by: 1)situations where the sidewall thermal regime dictates a certaincharacter of flows in the region near the wall; and/or 2)non-uniformities (however insignificant) of heating from below and/orcooling from above.

FIG. 21A-C depict roll patterns in a circular container. FIG. 21Adepicts concentric rolls formed with stronger forcing. In someembodiments, the wall that exerts stronger forcing may create anaxisymmetric system of rolls (see FIG. 21A). The effect of the lessforcing wall may also be sufficient for axisymmetric convection but maynot be strong enough for circular rolls next to the wall to be stable.Cross-roll instability may occur, resulting in development of asecondary flow in the form of short roll segments directed alongcontainer radii and abutting against the wall. These cross rolls mayoccupy an annular region of width as seen in FIG. 21B.

FIG. 21B depicts concentric rolls formed with weaker forcing andsuperposed by short crossed rolls near the wall.

FIG. 21C depicts straight rolls formed from a disordered pattern. Insome embodiments, it may be possible to obtain a set of almost straightrolls even if the wall with stronger forcing is used. If fluid patternmotions are sufficiently vigorous (developing initially little-orderedflow), formed rolls that are weakly curved may appear; and in thosenear-wall regions, the rolls may make small angles with the wall therebycreating short cross rolls.

FIG. 22 depicts eccentric annular rolls in a cylindrical vessel 106 insome embodiments. Axisymmetric roll patterns may be susceptible to aparticular instability which may manifest itself more appreciably as theRayleigh number increases.

It will be appreciated that the use of shapes or surfaces within or onthe base and/or walls of the vessel may promote bubble nucleation forthe onset of more rapid boiling. Square edges such as those depicted inFIGS. 7B, 8, and 14B may assist as nucleation points. Barbs, points,and/or roughened surfaces on the inner base or inner walls of the vesselmay also be utilized as nucleation points. Bubble nucleation may alsocontribute to, or induce, convection in the contained fluid.

The present invention is described above with reference to exemplaryembodiments. It will be appreciated that various modifications may bemade and other embodiments can be used without departing from thebroader scope of the present invention. Therefore, these and othervariations upon the exemplary embodiments are intended to be covered bythe present invention.

We claim:
 1. An article of manufacture comprising: a wall portion havinga wall inner surface and a wall outer surface; a base portion having abase inner surface and a base outer surface, at least a portion of thewall portion and the base portion forming a vessel to retain fluidtherein, at least part of the base portion configured to receive heatfrom a heating source; and a plurality of shaped portions extendingabove the base inner surface or the wall inner surface, a top of each ofthe plurality of shaped portions being opposite a bottom of each of theplurality of shaped portions, the plurality of shaped portions of thebase inner surface and/or the inner wall surface being shaped to have1.2 or more times surface area than a surface of the corresponding flatsurface, each shaped portion of the base inner surface including atleast three sides extending from the bottom to the top, the top of eachof the plurality of shaped portions being hexagonal in shape, each ofthe plurality of shaped portions capable of supplying heat from thesides to fluid adjacent to the sides of at least one other shapedportion of the plurality of shaped portions, the plurality of shapedportions of the base inner surface or the wall inner surface includingthe hexagonal shaped tops of the plurality of shaped portions and sidesof the plurality of shaped portions to assist in uneven heat transferfrom the heating source to the fluid retained in the article ofmanufacture.
 2. The article of manufacture of claim 1, wherein thearticle of manufacture is a kettle.
 3. The article of manufacture ofclaim 1, wherein at least two of the plurality of shaped portions havedifferent heights extending above the base inner surface or the wallinner surface.
 4. The article of manufacture of claim 1, wherein thebase portion comprises at least two different metals.
 5. The article ofmanufacture of claim 1, wherein each of the plurality of shaped portionsare hexagonal in shape.
 6. The article of manufacture of claim 1,wherein subsets of the plurality of shaped portions are evenly arranged.7. The article of manufacture of claim 1, wherein subsets of theplurality of shaped portions are arranged in one or more lines.
 8. Thearticle of manufacture of claim 1, wherein the plurality of shapedportions of the base inner surface or the wall inner surface includingthe hexagonal shaped tops of the plurality of shaped portions and thesides of the shaped portions are configured to assist in uneven heattransfer in the fluid of the article of manufacture and decrease timeneeded to heat the fluid to a desired temperature.
 9. The article ofmanufacture of claim 1, wherein the article of manufacture is a pot. 10.The article of manufacture of claim 1, wherein the base outer surfacefurther comprises one or more other shaped portions extending from thebase outer surface, the one or more other shaped portions to assist inuneven heat transfer from the heating source to the fluid in the articleof manufacture.
 11. The article of manufacture of claim 1, wherein theplurality of shaped portions of the base inner surface or the wall innersurface including the hexagonal shaped tops of the plurality of shapedportions and the sides of the shaped portions are configured to assistin creation of at least one two-armed spiral in the fluid that rotates.12. The article of manufacture of claim 11, wherein the plurality ofshaped portions of the base inner surface or the wall inner surfaceincluding the hexagonal shaped tops of the plurality of shaped portionsand the sides of the shaped portions are configured to induce one ormore dislocations in any of the at least one two-armed spiral.
 13. Thearticle of manufacture of claim 1, wherein the plurality of shapedportions of the base inner surface or the wall inner surface includingthe hexagonal shaped tops of the plurality of shaped portions and thesides of the shaped portions are configured to assist in creation of aplurality of three-dimensional cells in the fluid in the article ofmanufacture.
 14. The article of manufacture of claim 1, wherein in theplurality of shaped portions of the base inner surface or the wall innersurface including the hexagonal shaped tops of the plurality of shapedportions and the sides of the shaped portions are configured to assistin creation of a plurality of three-dimensional cells in contact withthe surface of the fluid in the article of manufacture.
 15. The articleof manufacture of claim 1, wherein the hexagonal shaped tops areconfigured to provide nucleation points to assist and promote bubblenucleation for the onset of rapid boiling.
 16. The article ofmanufacture of claim 15, wherein the nucleation points assist with anonset of rapid heating and avoids superheating the fluid to avoiddangerous pressures and spills.
 17. The article of manufacture of claim1, wherein the hexagonal shaped tops are configured to assist in theformation of G-cell convection cells in a surface of the fluid in thearticle of manufacture.
 18. The article of manufacturer of claim 1,wherein the heating source is within the base portion.
 19. A methodcomprising: receiving one or more metals; and forming the metals into akettle, the kettle including a wall portion, a base portion, and aplurality of shaped portions, the wall portion having a wall innersurface and a wall outer surface, the base portion having a base innersurface and a base outer surface, at least a portion of the wall portionand the base portion forming a vessel to retain fluid therein, at leastpart of the base portion configured to receive heat from a heatingsource, and the plurality of shaped portions extending above the baseinner surface or the wall inner surface, a top of each of the pluralityof shaped portions being opposite a bottom of each of the plurality ofshaped portions, each shaped portion of the base inner surface includingat least three sides extending from the bottom to the top, the top ofeach of the plurality of shaped portions being hexagonal in shape, eachof the plurality of shaped portions capable of supplying heat from thesides to fluid adjacent to the sides of at least one other shapedportion of the plurality of shaped portions, the plurality of shapedportions of the base inner surface or the wall inner surface beingshaped to have 1.2 or more time surface area than a surface of thecorresponding flat surface, the plurality of shaped portions of the baseinner surface or the wall inner surface including the hexagonal shapedtops of the plurality of shaped portions and sides of the plurality ofshaped portions to assist in uneven heat transfer from the heatingsource to the retained fluid in the article of manufacture.
 20. Anarticle of manufacture comprising: a wall portion having a wall innersurface and a wall outer surface; a base portion having a base innersurface and a base outer surface, at least a portion of the wall portionand the base portion forming a vessel to retain fluid therein, at leastpart of the base portion configured to receive heat from a heatingsource; and at least one shaped portion extending above the base innersurface or the wall inner surface, a top of the at least one shapedportion being opposite a bottom of the at least one shaped portion, theat least one shaped portion of the base inner surface including at leastthree sides extending from the bottom to the top, the top of the atleast one shaped portion being hexagonal in shape, the at least oneshaped portion capable of supplying heat from the sides to fluidadjacent to the sides, the at least one shaped portion of the base innersurface or the wall inner surface including the hexagonal shaped top andsides of the at least one shaped portion to assist in uneven heattransfer from the heating source to the retained fluid in the article ofmanufacture the at least one shaped portion being shaped to have 1.2 ormore surface area than a surface of the corresponding flat surface.